DE2551168A1 - PROCEDURE FOR LINING PIPES, CASTING FORMS OR OTHER TUBE-SHAPED OBJECTS - Google Patents

Description

FROM KREIStEt SCHONWALD MEYER EiSHOlD FROM KRElStER KELtER SELTiNO

PATENT LAWYERS Dr.-Ing. by Kreisler "t" 1973

Dr.-Ing. K. Schönwdd, Cologne Dr.-Ing. Th. Meyer, Cologne Dr.-Ing. K. W. Eishold, Bad Soden Dr. J. F. Fues, Cologne Dipl.-Chem. Afek von Kreisler, Cologne Dipl.-Chem. Carola Keller, Cologne Dipl.-Ing. G. SelHng, Cologne

AvK / Ax

5KOtNl November 13, 1975

DEICHMANNHAUS AT THE MAIN RAILWAY STATION

English Clays Lovering Poohin & Company Limited, John Keay House, St. Auste11, Cornwall (England).

Process for lining pipes, casting molds or

other tubular objects

(Addition to patent (patent application P 23 46 062.0))

The subject of the main patent ........ (patent application P 23 46 062.0) is a method for lining pipes, Molds or other tubular or hollow cylindrical objects with a hardenable material that can be incorporated into the Tube can be inserted in liquid form and is capable of hardening into a solid material. The procedure is characterized in that the tube is at a predetermined acute angle with its longitudinal axis inclined to the horizontal, a selected amount of a liquid at a predetermined speed Introduces material into the upper part of the pipe, the angle of inclination of the pipe and the rate of introduction of the liquid material are determined so that the liquid material that is first introduced into the pipe, flows along the inner wall of the pipe to a predetermined lower part of the pipe at the same time, which is necessary to complete the introduction of the entire selected amount of the liquid material, 609823/1039

Telephone: (02 21) 23 45 41 - 4 Telex: 688 2307 dopa d Telegram: Dompatent Cologne

wherein the material spreads along the length of the pipe ■ is, then brings the pipe into a horizontal position and then rotates the pipe around its longitudinal axis, around the liquid material around the inside of the pipe wall too distribute, and the turning continues until the material is cured.

Bei'Girier preferred embodiment of the method of Main patent becomes after the introduction of the liquid material. , and at the beginning of the rotation a hot gas, e.g. air, blown through the Rohi * to remove entrained air bubbles in to remove the liquid.

Object of the present invention, which is an improvement; en! SVexperienced in the main patent is a Method of lining pipes or other tubular structures or, hollow cylindrical objects, below. .. referred to as lohr, with a permanent and permanent coating made of thermosetting plastic, which is embedded in the Tube in Elorm one made of a prepolymer and a curing agent existing liquid mixture, which is able to solidify to an elastic solid material, introduced become kanij, whereby the pipe is brought into a position in which its longitudinal axis is inclined at a predetermined acute angle to the horizontal, the liquid mixture in a predetermined amount per unit time in an upper part of the pipe, whereby the first in the tube introduced liquid mixture along the inner wall of the pipe flows and the mixture is distributed over a certain length of the pipe will; introduces the liquid mixture into the tube for a predetermined time, the tube into the Brings horizontal position and rotates the pipe around its longitudinal axis, around the 'liquid mixture over .the entire inner wall of the pipe to distribute, and the turning continues until "The plastic has solidified. The method is characterized in that one just before the end of the pipe or . upon completion of the introduction of the chosen amount of

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liquid mixture brings in the horizontal position and after starting to rotate to achieve an initial Distributing the material around the inside of the pipe a gas, e.g. air, at a temperature which is above that prevailing Temperature of the lining material is, axially blows through the pipe for a relatively short time and thereby entrained air bubbles in the liquid material] removed.

The time during which the hot air is blown through the pipe depends on various factors, e.g. the length of the pipe and the lining material, however, proved to be the case with the special lining material described in the Main application is described, i.e. in the case of a mixture of the polyether containing terminal isocyanate groups "Adiprene" with 4,4V-methylenebis (2-chloroaniline) (MOCA), a blowing time of 30 seconds for 3.05 m long pipes and a blowing time of 45 seconds for tubes of one length 6.1 m is sufficient. These numbers apply to tubing with an inner diameter of 6 inches (152.4 mm) and larger.

In the case of pipes with a smaller diameter, it is possible to rotate the pipes at such a high speed that Blowing with hot air is not necessary, as the bubbles of entrained air are created by the action of centrifugal force on the mixture can be removed automatically.

For pipes with an inside diameter of 6 inches (152.4 mm) or more, the rotational speed can be affected by irregularity A practical limit can be set in the pipe so that the measure of blowing hot air through to remove the Air becomes necessary.

When using a polyurethane mixture of "Adiprene" and MOCA, the service life is relatively short or has pot life, the hot air must be blown through the tube before 6 minutes have elapsed since the start of spinning are. Preferably "is the hot air within a time from 1.5 to 4 minutes after starting spinning through the

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Blown pipe.

In a special embodiment of the method of The main patent is the pipes to be lined with end flanges provided, are screwed to the cover with a spacer interposed, creating an annular cavity on the radially extending inner part each flange is formed so that end faces of lining material that with the actual lining material related, are formed. Each lid is versed with a centrally aligned hole. hen, which is much smaller than the inner diameter of the pipe after lining.

It has now been found that in this particular embodiment When the hot air stream is blown through the tube, open the small hole in the cover at the outlet end The rapid flow of hot air through the pipe is hindered. It is therefore advisable in this case to open the hole in the Make lid on the outflow side larger than the hole in the deekel at the end through which the flow of hot air is introduced.

However, this has the disadvantage that if between Moment in which the introduction of the liquid material has ended, and there is a time delay in the introduction of the pipe in the horizontal position of the liquid material in the inclined pipe the danger consists that liquid material from the enlarged hole flows out in the lid at the lower end of the tube. To avoid this risk, it is suggested that the pipe just before the completion of the introduction of the liquid material to bring into the horizontal position.

According to a particular feature of the invention, in the method for lining pipes, the pipe is brought into the horizontal position before the end of the introduction of the selected amount of the liquid mixture and afterwards

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Completion of the introduction of the liquid mixture started rotating.

The invention can be practiced in various ways, however, the following is given as an example a specific embodiment with reference to the Illustrations described.

Fig. 1 shows a graph of the required Raising of the end (L) depending on the outer diameter of a pipe that is 6.1 m long to be lined.

Fig. 2 shows in longitudinal section an inclined pipe, in which a lining material based on polyurethane in liquid Form is introduced.

Fig. J5 shows the pipe shown in Fig. 1 in a horizontal direction Position shortly after starting to turn while hot air is blown through.

Fig. K shows schematically an arrangement for supplying hot air to the pipe.

one

The lining process is generally / in manner performed as specifically stated in the main application.

is described. A polyurethane is used as the lining material, which consists of terminal isocyanate groups containing polyester "Adiprene" and M.O.C.A. consists, which are prepared and continuously fed to a mixing head which can be operated in such a way that the Reactants mixed and fed to the pipes to be lined. The pipes 10 are prepared, by cleaning them and lining them with a suitable binding agent, the lids 12 and 12A on the placed on the respective ends and preheated the pipes

J) O will be.

Two preheated tubes 10 are in the "filling" and

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Turning station on supports 18 and 19 (Fig. 2) out. The support 18 of each tube is then raised slightly to incline the tubes at a certain angle. This Angle depends on the length of the pipe, the diameter and the amount of lining material to be introduced away. Pig. 1 is a graph showing the required lift distance in inches at the top of the pipe for various outside diameters in inches. These values apply to pipes that have a length 6.1 m. and should be lined with a 9.5 mm (3/8 inch) thick liner. The graphic representation also shows the casting time T to be used for various points on the graph.

The pipes are now ready for the introduction of the liquid Polyurethane mixture. The mixing head is then started and a stop watch is operated at the same time to display the Measure casting time T. The polyurethane mixture is fed through a hose 21 at a rate of 10 kg / minute fed, the lower end 22 of which into a hole 15 of the cover 12 at the raised end of one of the tubes 10 is pushed.

The liquid polyurethane mixture designated by 23 in FIG. 2 the inclined pipe 10 flows down towards the lower end. Shortly before the predetermined Pouring time T, i.e. the time it takes to feed the selected amount of lining material in the predetermined Quantity per unit of time is required, the pipe 10 is guided in the horizontal position, while the Pouring continues. This is for the following reason:

When the pipe is held in an inclined position until the pouring is finished and a time lag between them Moment and the leadership of the pipe in the horizontal position is available, there is a risk that the liquid Mixture too strong - flows to the lower end of the pipe.

This has the undesirable consequence that the trained

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clothing is too thin at the insertion end and the lining material can flow out of the hole 15A in the cover 12A at the lower end of the tube.

The exact time at which the pipe is in the horizontal Location depends on the casting time, but it has generally been found that the pipe after approximately 4/5 to 9/10 of the complete casting time T should be carried out in the horizontal position. For example the Hohr at a time T of 5 minutes after 4.5 minutes and after a pouring time of 2 minutes about 1.75 minutes in the horizontal position.

At the end of the casting time with the now horizontal pipe 10, the pipe is driven with the help of driven rollers 30 and 31 with one for distributing the lining material rotated suitable speed. It is believed, that the liquid mixture during the first a few revolutions in the pipe under the influence of the combined rotary and gravity effect and air is trapped in the mixture.

As soon as the rotation speed is increased sufficiently, will the liner is held against the inner wall of the pipe by centrifugal force.

Uta to remove the entrained air becomes a stream of hot air blown through the pipe. That step is in Pig. 3 shown. Air that has a temperature between; 300 ° and 400 ° C is blown through an injection pipe 33, which is provided with a hood 34 to prevent make sure that the injection nozzle fills the hole 15 in the cover 12 and the hot air is blown axially down the pipe * If the hot air is not blown axially down the pipe, • the air can hit the lining directly, hit and burn the material. The hot air so that the lining material can initially spread around the pipe, about 2 to 3 minutes

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th after starting shooting for a proportionate short time, e.g. 30 seconds for a 3.05 m long Pipe and 45 seconds for a 6.1 m long pipe, blown through the rotating pipe.

Fig. 2 and Fig. 3 show that the centrally located hole 15A in the cover 12A is larger at the outlet end of the tube is than the hole 15 in the cover 12 at the inflow end. Of the The reason for this is that the hot air should flow quickly through the pipe. If hole 15A is not in enlarged in this way, the hot air would not flow through the pipe fast enough, so that uneven Results would be obtained.

It is believed that the hot air coming through the pipe flows, which has a temperature of about 100 ° (in this phase, causes the bubbles of entrained air to dissolve expand and burst, so that the entrained air is free and the lining formed becomes glass-like, smooth Surface has. If the entrained air bubbles are not removed, it is to be expected that the in the Finished lining depressions left behind are effective as centers of erosion and as a result of the Pipe flowing material that exerts an abrasive effect would lead to faster wear of the liner.

The hot air for blowing through the pipe is generated in the manner shown in FIG. A fan 35 supplies the air at a pressure of 762 to 889 mm water column to a heating pipe 36 through four inlet openings which are arranged at a distance around a central flame pipe 38 to which propane gas is supplied. A flame ignition, a flame detector, which serves as a safety device for monitoring the supply of propane gas, and a thermometer are arranged in the heating tube 36. The incoming air is heated by the propane flame, and this hot air is supplied to the injection pipe 33 under pressure.

98 23 / -QJ 40z?

After blowing the air through the pipe, the Injector removed, followed by about another 30 minutes is rotated until the polyurethane has hardened. The pipes are then kept at an elevated temperature for some time held until the polyurethane has fully cured and an elastic solid lining in 'the pipe has formed.

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Claims (9)

- ίο - Patent claims Method of lining pipes or other tubular or hollow cylindrical objects, hereinafter referred to as a pipe, with a permanent and permanent coating made of thermosetting plastic, which is inserted into the Tube in the form of a liquid mixture consisting of a prepolymer and a curing agent, which becomes a elastic solid material is able to solidify, can be introduced, whereby the tube is brought into a position in which its longitudinal axis is inclined at a predetermined acute angle to the horizontal, the liquid mixture in a predetermined amount per unit time in an upper part of the pipe, whereby the first in The liquid mixture introduced into the tube flows along the inner wall of the tube and the mixture flows over a certain length of the tube is distributed; introduces the liquid mixture into the tube for a predetermined time, the tube into the Brings horizontal position and rotates the pipe around its longitudinal axis, around the liquid mixture over the entire inner wall of the pipe, and the rotation continues until the plastic has solidified, thereby characterized in that one the tube shortly before completion or at the end of the introduction of the selected amount of liquid mixture brings in the horizontal position and after starting to rotate to achieve an initial Distributing the material around the inside of the pipe a gas, e.g. air, at a temperature above that prevailing Temperature of the lining material is, axially blows through the pipe for a relatively short time and thereby removed air bubbles entrained in the liquid material. 809823/1039 - li - 2. The method according to claim 1, characterized in that that a polyurethane is used as the thermosetting plastic, which consists of an elastomeric urethane prepolymer e.g. a polyether with terminal isocyanate groups, by reaction with a suitable hardening agent such as a diamine. 3. Method according to claim 1 or 2, characterized in that that the hot "gas" within the period of time from the point in time at which the tube has a sufficient rotational speed has reached to the lining material by the centrifugal force on the inside of the Pipe until 6 minutes have elapsed after the start of spinning for a relatively short period of time blows through the pipe. 4. The method according to claim 1 to jj, characterized in, that the hot gas is released through the tube within 1.5 to 4 minutes after the start of spinning blows. 5. The method according to claim 1 to 4, characterized in that the hot gas is blown through the tube for a period of 20 to 60 seconds, preferably J> 0 to 45 seconds. 6. The method according to claim 1 to 5> wherein the pipe is on each end is provided with a flange to which a cover is attached, characterized in that that each lid is provided with a centrally located hole and the hole in the lid at the end where the hot gas flowing out is larger than the hole in the lid at the end through which the gas flow is introduced. h 0 9 H 2 3/1 QJ 9 7. The method according to claim 1 to 6, characterized in that the tube is brought into the horizontal position shortly before the end of the introduction of the selected amount of the liquid mixture. 8. The method according to claim 1 to 7, characterized that you bring the pipe in the horizontal position after about 4/5 to 9/10 of the for the introduction of liquid mixture in the tube in the certain amount per unit of time certain time have elapsed. 9 .. The method according to claim 1 to 8, characterized in that the lining material has a temperature of about 100 ⁰ C and the hot gas has a temperature of 300 ° to 400 ° C at the beginning of the turning.